Low silicon non-grain-oriented electrical steel: Linking magnetic properties with metallurgical factors

Commercial supply, from several steel manufacturers, of low-silicon non-grain-oriented electrical steel was monitored over a span of several years. A total of 51 samples were selected—selected from many hundreds on the basis of large differences in magnetic properties, but absence of significant variations in chemistry (other than differences in silicon percentage). The selected samples were analyzed for crystallographic texture and for grain size.     

Analysis of finite element method for one-dimensional time-dependent Schrödinger equation on unbounded domain

This paper addresses the theoretical analysis of a fully discrete scheme for the one-dimensional time-dependent Schrödinger equation on unbounded domain. We first reduce the original problem into an initial-boundary value problem in a bounded domain by introducing a transparent boundary condition, then fully discretize this reduced problem by applying Crank–Nicolson scheme in time and linear or quadratic finite element approximation in space. By a rigorous analysis, this scheme has been proved to be unconditionally stable and convergent, its convergence order has also be obtained. Finally, two numerical examples are performed to show the accuracy of the scheme.     

Natural and artificial weathering characteristics of stabilized acrylic–urethane paints

Depth-profiling by Fourier transform infrared (FTIR) spectroscopy, dynamic mechanical analysis (DMA), microhardness and scanning electron microscopy (SEM) observations have been used to monitor degradation chemistries in two-package acrylic–urethane coatings when exposed to different exposure conditions. Three artificial and three natural weathering protocols (QUV, ASTM D5894, ISO20340, Pipady (south of France), Bandol (south of France) and Kure Beach (USA)) were selected for this study. The same chemical events were found to occur under all conditions, particularly under natural and artificial exposures. Both loss of the amide II band at 1520 cm⁻¹ and carbonyl growth occurred but at relatively low rate owing to the presence of hindered-amine light stabilizers in the film. A less typical loss of urea biuret linkages also occurs during all exposures and results in a change in the balance between urethane and urea links across the depth of the film during weathering. The chemical degradation of the polymer matrix involves the formation of species that are readily ablated from the surface and results in loss of gloss, increase in hardness and a rougher topology. The dramatic loss of gloss observed after Pipady and Bandol exposures show that loss of gloss should not be systematically correlated to the advance in chemical degradation.     

Mathematical modelling of influence functions in computer-controlled polishing: Part I

Computer-controlled polishing (CCP) is commonly used to finish high-quality surfaces, such as optical lenses. Based on magnetorheological finishing (MRF), a mathematical model to calculate the polishing tool characteristic (influence function) was developed and verified experimentally. The first part of this paper introduces the model to predict the size and shape of an influence function. The second part of this paper describes the calculation of the distribution of material removal within the size of an influence function. The model supersedes the current cumbersome procedure for determining an influence function and thus results in considerably improved and more economical manufacture. Furthermore, the model enables the quality of the final surface to be enhanced when polishing complex, for example aspherical or free-form, workpiece geometries and provides the first step in the application of time-variant influence functions.     

Microdroplet size prediction in microfluidic systems via artificial neural network modeling for water-in-oil emulsion formulation

In this paper, an experimental study and modeling by artificial neural networks were carried out to predict the generated microdroplet dimensionless size in a microfluidic system in order to formulate a water-in-oil emulsion. The various parameters that affect the size of microdroplets (flow rates, viscosities, surface tensions of both the two phases and the diameter of the microchannel) are studied and further grouped into dimensionless numbers; we used these numbers as input to the neural network and the dimensionless length as output. The better neural network architecture has 10 neurons in the hidden layer with a mean square error of 1.4 10^?6 and a determination’s coefficient near 1 value. The relative importance of inputs on the size of the microdroplets has been determined using the Garson algorithm and the results are in good agreement with other works.     

基于金纳米颗粒负载的金属有机骨架材料的癌胚抗原传感器的研制

以负载Au的金属有机骨架材料(AuNPs/Cu-TPA)标记CEA抗体(Ab2)为信号探针,通过电还原的方法将氧化石墨烯还原到电极上,研制了一种捕获CEA抗体(Ab1)的电化学免疫传感器,并将其应用于癌胚抗原(CEA)检测.所合成的MOFs材料中含有大量Cu2+,且电化学信号比较稳定,因此可以通过检测MOFs材料中Cu2+的信号实现对CEA的检测.此信号探针不需要预处理和酸处理,易负载贵金属从而固定抗体,大大简化了检测步骤并缩短了检测时间.此传感器对CEA的检测灵敏度好,操作简便.在最优实验条件下,此传感器的线性范围为0.1～ 80 ng/mL,检出限为0.03 ng/mL,线性相关系数为0.9887,可用于真实样品中CEA的测定.     

三峡库区大石板滑坡区排水系统效果评估

结合三峡库区大石板滑坡工程实例 ,以连续 36天的降雨过程为条件 ,利用已有的地下水位观测资料 ,采用人工神经网络方法预测滑坡内地下水位在排水工程实施前后的变化 ,以此作为非饱和—饱和—非衡定地下渗流计算的特定水头边界。根据计算的地下水位进行滑坡稳定性分析 ,结合稳定分析成果对排水系统工程的效果进行评价。结果表明 ,地下排水工程的实施可较大幅度地提高滑坡的稳定性。     

Automated chemiluminescent dual-analyte immunoassay based on resolved immunosensing channels

A novel system of series-wound immunosensing channels (SWIC) was proposed for automated chemiluminescent (CL) dual-analyte immunoassay by immobilizing respectively different capture antibodies on the inner walls of series-wound glass channels. This system could use a single enzyme as label to perform multiplex immunoassay in one fluid way. Using α-fetoprotein (AFP) and carcinoembryonic antigen (CEA) as model analytes, the mixture including AFP, horseradish peroxidase (HRP)-labeled anti-AFP antibody, CEA and HRP-labeled anti-CEA antibody was introduced into the SWIC for carrying out the on-line incubation. Upon injection of CL substrate the CL signals from the two immunosensing channels were conveniently resolved and near-simultaneously collected with the aid of optical shutter. AFP and CEA could be rapidly assayed in the ranges of 1.0-100 and 1.0-80 ng/ml with detection limits of 0.41 and 0.39 ng/ml, respectively. The assay results of clinical serum samples were in an acceptable agreement with the reference values. This designed flow-through immunosensing system based on SWIC provided an automated, reusable, simple, sensitive and low-cost approach for multianalyte immunoassay.     

The artificial binaphthyl amino acid 6-amino-6′-carboxyethyl-2-methoxy-2′-hydroxy-1,1′-binaphthyl (Bna): synthesis and assembly of Bna peptides

The new binaphthyl-based amino acid 6-amino-6′-carboxyethyl-2-methoxy-2′-hydroxy-1,1′-binaphthyl (Bna) is presented, which combines the axially chiral binaphthyl core, a phenolic OH-group as well as terminating amino and carboxyl groups in one structure. The large aromatic rings of the compound provide molecular spacing and π-surface attraction in assembled Bna oligoamides. The synthesis of Bna derivatives is reported, both with the (R)- and with the (S)-binaphthyl skeleton. Several dipeptides of (R)- or (S)-Bna units combined with natural amino acids, were prepared as ‘building blocks’ for the synthesis of extended Bna peptides. The tetrapeptide Boc-(S)-Val-(S)-Bna(OH)-(S)-Val-(S)-Bna(OPiv)-O-n-But (12) and the pentapeptide Boc-(S)-Val-(S)-Bna(OH)-(S)-Val-(S)-Bna(OH)-Gly-OH (13) were prepared via conventional solution phase synthesis and solid phase synthetic techniques, respectively. Compound 12 shows an interesting dynamic ¹H NMR spectrum suggesting compact and aggregated forms in dichloromethane. Compound 13 accelerates the enolisation of acetone. The use of more complex Bna peptides as organo catalysts is proposed.